Space and weight considerations in vehicles most often require the use of convertible seat-beds. Conventional seat-beds such as those shown in U.S. Pat. No. 4,321,176, and related patents utilize a well-known linkage system to pivotally connect the seat support and back support to the chair-bed frame.
Prior art linkage systems, including power driven systems, were very clumsy and unsturdy. Since the linkage in most cases is located towards the peripheral edges of the frame, it bears the weight of the seat and back supports in a manner which requires strong, durable links to avoid breakage or collapse. Further, DOT requirements for these linkage systems are often set at artificially high levels in order to ensure their safety.
Prior art linkage systems often fail to meet these rather stringent standards. Furthermore, these prior art systems are often difficult to operate manually, particularly as they age and the parts become worn due to constant use.